Monitoring systems are known to protect life and property within protected areas. Such systems are typically based upon the use of one or more sensors that detect threats within the areas.
Threats to people and assets may originate from any of a number of different sources. For example, a fire may kill or injure occupants who have become trapped by a fire in a building. Similarly, carbon monoxide from a fire may kill people in their sleep.
In order to address these threats, a number of fire sensors and alarm devices may be distributed throughout a home or business. The fire sensors may be based upon any of a number of different detection technologies (e.g., smoke, heat, toxic gases, etc.). The alarm devices may also be based upon different technologies (e.g., sounders, strobes, voice alarm speakers, etc.) and may even be integrated into the fire sensors.
In most cases, fire detectors are connected to a local control panel. Large systems may include a number of networked control panels. In the event of a threat detected via one of the sensors, the control panel may activate the alarm devices. The control panel may also send a signal that alerts a central monitoring station.
The fire sensors may be connected to the local control panel via a two-wire (2-wire) loop. The 2-wire loop may serve the dual functions of providing power to the sensors as well as providing a communication connection.
While fire alarm systems work well, they can sometimes fail to properly notify occupants of threats from fires originating within a secured area. In many cases, the failure may be attributed to failure of the communication connection provided through the 2-wire loop. This may cause some fire detectors and/or alarm devices to fail to operate properly or to otherwise report a fire. Accordingly, a need exists for better methods and apparatuses for detecting failure of 2-wire loops.